1. Field of the Invention
The present invention relates to a conductive fluorosilicone rubber composition providing a conductive fluorosilicone rubber which is particularly small in tension set, rich in rubber elasticity, and excellent in heat resistance.
2. Description of the Prior Art
Conductive elastomers are broadly used in, for example, rubber contacts, static electricity, removal of electricity, shield of electromagnetic waves, and materials for various conductive rolls. As raw materials of the conductive elastomers, there are used various materials such as silicone, polyurethane, polyethylene, polypropylene and natural rubbers, depending on properties such as rubber strength, abrasion, and fire retardance which are required in accordance with the purposes of the conductive elastomers to be used.
As methods for rendering electrical conductivity to elastomers, there are used an electron transfer type in which a conductive carbon or a conductive metal powder is mixed, and an ion conductive type in which an ion conductive agent such as a lithium ion conductive agent is mixed. Generally speaking, the electron transfer type is broadly used.
Among the conductive elastomers, the conductive silicone rubber is excellent in properties such as heat resistance, cold resistance, and weatherability, so that it is used in rubber contacts and materials for business machines. Especially, a fluorosilicone rubber having a 3,3,3-trifluoropropyl group at its side chain is excellent in not only the above properties but also solvent resistance. There is a defect that addition of carbon to the fluorosilicone rubber for providing the same with electric conductivity results in lowering of mechanical strength and rubber elasticity. Particularly, the rubber elasticity typically represented by tension set is extremely lowered and heat deterioration is increased, so that there occurs a problem in use as diaphragms, O-rings or oil seal materials, which are typical parts of the fluorosilicone rubber, as parts of transportation or parts of petroleum-related apparatus and instrument.
In the case of the ion conductive fluorosilicone rubber, it is required to add a large amount of a transmitting substance (binder) for the ion conductive agent to the fluorosilicone rubber. This causes hindrance in crosslinking of the rubber material and decrease in the mechanical strength of a cured rubber. Thus, any practical product has not been known yet.